Note 3 - Periodic Pension Expense - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Service cost - benefits earned during the period	$ 27	$ 17	$ 81	$ 49
Interest cost on projected benefit obligation	242	241	727	724
Expected return on plan assets	(429)	(305)	(1,288)	(914)
Recognized actuarial loss	284	253	850	800
Settlement loss		158		435
Net periodic pension cost	$ 124	$ 364	$ 370	$ 1,094